Cal. Sts. & Hy. Code § 2007
The road commissioner shall each year prepare a tentative road budget covering all proposed expenditures for the ensuing fiscal year for county road purposes. The road commissioner shall submit the budget to the board of supervisors in accordance with Chapter 1 (commencing with Section 29000) of Division 3 of Title 3 of the Government Code and in the form and manner prescribed by the Controller and at the same time as other county departments submit their recommended budgets.
The board of supervisors shall hold public hearings on the proposed road budget at the same time as the general county budget is considered and after like notice. In adopting the budget, the board may make such changes and revisions as it considers will subserve the public interest.
After adoption of the budget by the board of supervisors, the road commissioner shall not obligate or expend funds appropriated for county road purposes other than as set forth in the budget as adopted. However, the board of supervisors may, by appropriate action at any regular or special meeting, authorize the cancellation or transfer, in whole or in part, of any appropriation or appropriations set forth in the budget and reappropriate funds thus canceled for road purposes not set forth in the budget or to expenditure classifications insufficiently provided for where this action will best serve the interests of the people. Funds transferred pursuant to this section, or as authorized by the board of supervisors, shall immediately be made available for expenditure by the road commissioner for road purposes.
Ca. Sts. and High. Code § 2007